test: add test for per-attack image directories and improve error handling

- Add test_generate_test_cases.py to verify each attack uses its own image directory
- Improve error messages in unified_registry for failed imports with more context
- Add null checks in generate_test_cases.py for attack initialization failures
- Reduce excessive max_tokens in judge_utils from 130000 to 10000 for efficiency
- Add missing ThreadPoolExecutor import in qr/attack.py
- Fix missing newline in pyproject.toml

core/unified_registry.py

@@ -154,8 +154,10 @@ class UnifiedRegistry:
                 )
                 return cls
         except (ImportError, AttributeError) as e:
-            self.logger.debug(
-                f"Unable to import {type_name} '{name}' from mapping: {e}"
+            self.logger.warning(
+                f"Failed to import {type_name} '{name}': {e}. "
+                f"This usually means missing dependencies. "
+                f"Module: {module_path}, Class: {class_name}"
             )
             return None
         except Exception as e: